1. Field of the Invention
The present invention relates to processes for recycling glass, and more particularly, to a process for separating the glass components from nonglass components of glass containing articles.
2. Description of the Invention Background
In 1990, an estimated 18-20 million television sets were sold in the United States. A single television manufacturing facility may produce from 7,000 to about 15,000 television picture tubes per day. Of these, between about five to seven percent are rejected due to some defect rendering them unsuitable for sale. Thus, at a single manufacturing facility, hundreds of TV tubes are discarded each day amounting to several hundred tons of TV tube waste each month. The traditional means of disposing of the waste has been to put it in land fills.
A television tube typically contains glass components and nonglass components. The glass components include a front panel, which is up to two inches thick in places, and a conical funnel section. The nonglass components include paper, plastics, ceramics and metals in the form of the electronic gun, clips, masks, straps and a lead frit used to join the panel glass to the funnel glass. A graphite acrylic coating typically is applied to the external surfaces of the panel glass and the funnel glass. The internal surface of the panel glass is also coated with, for example, aluminum, phosphor and graphite. The internal surface of the funnel glass may be coated with graphite, iron oxide and sodium silicate.
Because the glass TV tubes exhibit toxic waste characteristics due to leaching of lead from the frit and funnel, they are disposed of as a hazardous waste. Simply burying the TV tubes is no longer permissible. Transport of the waste to approved toxic land fills is costly.
Heretofore, there has been no effective means of recycling the waste TV tubes or other articles made of glass and nonglass components. The structural mixture of glass and nonglass components and the inorganic and organic coatings on the glass in TV tubes makes them unacceptable for recycling by conventional glass or metal recycling methods. In addition, the ceramic components in the TV tubes would poison the glass for most further uses if the glass and ceramics are mixed. Avoiding such a mixture was heretofore very difficult. Crushing the discarded TV tubes by conventional means only inextricably mixes the glass and nonglass components. The safe disposal and/or recycling of TV tubes and similar mixed glass and nonglass articles has become a problem.
There is a need for a process for separating the glass and nonglass components of a TV tube or similarly structured article. There is a further need for a process for sizing and cleaning the separated glass for recycling. Finally, there is a need for a process for separating different types of glass, such as the panel glass from the funnel glass, in an economic and easy to use process.